21203121011 has 8 divisors (see below), whose sum is σ = 21735723600. Its totient is φ = 20675427552.

The previous prime is 21203120971. The next prime is 21203121019. The reversal of 21203121011 is 11012130212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21203121011 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21203121019) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1218536 + ... + 1235813.

It is an arithmetic number, because the mean of its divisors is an integer number (2716965450).

Almost surely, 2^21203121011 is an apocalyptic number.

21203121011 is a deficient number, since it is larger than the sum of its proper divisors (532602589).

21203121011 is a wasteful number, since it uses less digits than its factorization.

21203121011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2454565.

The product of its (nonzero) digits is 24, while the sum is 14.

Adding to 21203121011 its reverse (11012130212), we get a palindrome (32215251223).

The spelling of 21203121011 in words is "twenty-one billion, two hundred three million, one hundred twenty-one thousand, eleven".